I'd start here. Actually, the whole thing is worth reading. Paladins, especially Ret, don't have a single faceroll button anymore, you need to pay attention to what's going on and react based on priorities. My Ret uses a 3step toggle and that still doesn't even cover procs {AoW and DP} or AOE {Cons or AW}, which I do manually.

The best advice I can give is drop the Ret for something else. Spec him prot or holy and solo-level him through dungeons if you want and boost the rest of your team, then go back and boost a replacement. Or make him the new tank or healer for your group and spec your current tank/healer out to DPS. I don't know what your current group setup is, but ret really isn't the best option for boxing for a number of reasons these days.